Many different types of modeling compositions for creating figures or sculptures have been introduced over time, particularly for use as craft products by children, and for general artistic purposes. U.S. patents which relate to moldable compositions include U.S. Pat. No. 6,359,057 to Li, U.S. Pat. No. 5,171,766 to Mariano et al., U.S. Pat. No. 5,364,892 to Miller et al., U.S. Pat. No. 5,498,645 to Mariano et al., and U.S. Pat. No. 5,506,280 to Miller et al., which are incorporated by reference herein.
Some moldable compositions utilize “polymer clay technology,” whereby particles of polyvinyl chloride (PVC) are plasticized with typical plasticizers (e.g., phthalates, diesters, triesters, etc), and heating these compositions in the oven melts the PVC particles to form a hardened article. A drawback of this technology is that polymer clay must be hardened in an oven at an elevated temperature, and there is a risk of thermal degradation of the PVC which releases hazardous HCl. Also, polymer clay requires kneading or other physical manipulation to make it soft and pliable for use.
There remains a need for moldable compositions that overcome these drawbacks by having the ability to harden at ambient temperature (i.e., by air-drying), that are already soft so that they require no kneading prior to use, and that do not release HCl or easily thermally degrade.